Filter media can be used to remove contamination in a variety of applications. Depending on the application, the filter media may be designed to have different performance characteristics. For example, a filter media may be designed to have performance characteristics suitable for hydraulic applications which involve filtering contamination in pressurized fluids (e.g., liquid). Filter media may also be designed to have performance characteristics suitable for applications that involve filtering in air.
In general, filter media can be formed of a web of fibers. The fiber web provides a porous structure that permits fluid (e.g., hydraulic fluid, air) to flow through the filter media. Contaminant particles contained within the fluid may be trapped on the fibrous web. Filter media characteristics, such as fiber diameter and basis weight, affect filter performance including filter efficiency, dust holding capacity and resistance to fluid flow through the filter.
Certain filter media include webs formed of glass fibers. Such media can exhibit brittle characteristics, which generally make the filter media sensitive to handle and difficult to pleat. In some filter media, synthetic components (e.g., polyvinyl alcohol) are added to the web to improve mechanical properties such as strength. However, such components can negatively effect filtration properties including lowering dust holding capacity and causing instabilities in efficiency over time.
In general, there is a need for a glass fiber filter media which has a desirable balance of properties including high flexibility and strength, high dust holding capacity and a stable efficiency over the life time of the filter media.